scholarly journals Plasticity in a Drosophila wing circuit supports an adaptive sleep function

2019 ◽  
Author(s):  
K. Melnattur ◽  
B. Zhang ◽  
P.J. Shaw
Keyword(s):  
Sensory Neurons ◽  
Ecological Factors ◽  
Structural Plasticity ◽  
Projection Neurons ◽  
Behavioural Flexibility ◽  
Sensory Cues ◽  
Neural Pathway ◽  
Drosophila Wing ◽  
Central Brain ◽  
Influential Theory

AbstractSleep is a near universal phenomenon whose function remains controversial. An influential theory of sleep function posits that ecological factors that place animals in harm’s way increase sleep as a state of adaptive inactivity. Here we find that manipulations that impair flight in Drosophila increase sleep. Further, we identify a novel neural pathway from peripheral wing sensory neurons to the central brain that mediates the change in sleep. Moreover, we show that flight impairments activate and induce structural plasticity in specific projection neurons to support increases in sleep over days. Thus, chemosensory neurons do not only signal sensory cues but also appear to provide information on wing-integrity to support behavioural adaptability. Together, these data provide mechanistic support of adaptive increases in sleep and highlight the importance of behavioural flexibility for fitness and survival.

scholarly journals Disrupting flight increases sleep and identifies a novel sleep-promoting pathway in Drosophila

2020 ◽  
Vol 6 (19) ◽  
pp. eaaz2166
Author(s):  
K. Melnattur ◽  
B. Zhang ◽  
P. J. Shaw
Keyword(s):  
Sensory Processing ◽  
Environmental Changes ◽  
Ecological Factors ◽  
Cytosolic Calcium ◽  
Projection Neurons ◽  
Axonal Projections ◽  
Regulatory Circuit ◽  
Central Brain ◽  
Insight Into ◽  
Target Projection

Sleep is plastic and is influenced by ecological factors and environmental changes. The mechanisms underlying sleep plasticity are not well understood. We show that manipulations that impair flight in Drosophila increase sleep as a form of sleep plasticity. We disrupted flight by blocking the wing-expansion program, genetically disrupting flight, and by mechanical wing perturbations. We defined a new sleep regulatory circuit starting with specific wing sensory neurons, their target projection neurons in the ventral nerve cord, and the neurons they connect to in the central brain. In addition, we identified a critical neuropeptide (burs) and its receptor (rickets) that link wing expansion and sleep. Disrupting flight activates these sleep-promoting projection neurons, as indicated by increased cytosolic calcium levels, and stably increases the number of synapses in their axonal projections. These data reveal an unexpected role for flight in regulating sleep and provide new insight into how sensory processing controls sleep need.

scholarly journals Parallel visual pathways with topographic versus non-topographic organization connect the Drosophila eyes to the central brain

2020 ◽  
Author(s):  
Lorin Timaeus ◽  
Laura Geid ◽  
Gizem Sancer ◽  
Mathias F. Wernet ◽  
Thomas Hummel
Keyword(s):  
Visual Information ◽  
Visual Cues ◽  
Spatial Information ◽  
Central Complex ◽  
Structural Basis ◽  
Projection Neurons ◽  
Central Brain ◽  
Retinotopic Organization ◽  
Dendritic Fields ◽  
Parallel Visual Pathways

SummaryOne hallmark of the visual system is the strict retinotopic organization from the periphery towards the central brain, spanning multiple layers of synaptic integration. Recent Drosophila studies on the computation of distinct visual features have shown that retinotopic representation is often lost beyond the optic lobes, due to convergence of columnar neuron types onto optic glomeruli. Nevertheless, functional imaging revealed a spatially accurate representation of visual cues in the central complex (CX), raising the question how this is implemented on a circuit level. By characterizing the afferents to a specific visual glomerulus, the anterior optic tubercle (AOTU), we discovered a spatial segregation of topographic versus non-topographic projections from molecularly distinct classes of medulla projection neurons (medullo-tubercular, or MeTu neurons). Distinct classes of topographic versus non-topographic MeTus form parallel channels, terminating in separate AOTU domains. Both types then synapse onto separate matching topographic fields of tubercular-bulbar (TuBu) neurons which relay visual information towards the dendritic fields of central complex ring neurons in the bulb neuropil, where distinct bulb sectors correspond to a distinct ring domain in the ellipsoid body. Hence, peripheral topography is maintained due to stereotypic circuitry within each TuBu class, providing the structural basis for spatial representation of visual information in the central complex. Together with previous data showing rough topography of lobula projections to a different AOTU subunit, our results further highlight the AOTUs role as a prominent relay station for spatial information from the retina to the central brain.

scholarly journals Sensory neurons of the Atonal lineage pioneer the formation of glomeruli within the adult Drosophila olfactory lobe

Development ◽  
2002 ◽  
Vol 129 (5) ◽  
pp. 1251-1260 ◽  
Author(s):  
Dhanisha Jhaveri ◽  
Veronica Rodrigues
Keyword(s):  
Sensory Neurons ◽  
Glial Cells ◽  
Crucial Role ◽  
Sensory Innervation ◽  
Projection Neurons ◽  
Olfactory Lobe ◽  
Adult Drosophila

The first centers for processing of odor information by animals lie in the olfactory lobe. Sensory neurons from the periphery synapse with interneurons in anatomically recognizable units, termed glomeruli, seen in both insects and vertebrates. The mechanisms that underlie the formation of functional maps of the odor-world in the glomeruli within the olfactory lobe remains unclear. We address the basis of sensory targeting in the fruitfly Drosophila and show that one class of sensory neurons, those of the Atonal lineage, plays a crucial role in glomerular patterning. Atonal-dependent neurons pioneer the segregation of other classes of sensory neurons into distinct glomeruli. Furthermore, correct sensory innervation is necessary for the arborization of projection neurons into glomeruli and for the elaboration of processes of central glial cells into the lobe.

Olfactory Microcircuits in Drosophila Melanogaster

2017 ◽  
pp. 361-368
Author(s):  
Jürgen Rybak ◽  
Bill S. Hansson
Keyword(s):  
Drosophila Melanogaster ◽  
Sensory Neurons ◽  
Mushroom Body ◽  
Antennal Lobe ◽  
Odorant Receptor ◽  
Second Order ◽  
Projection Neurons ◽  
Order Processing ◽  
Vinegar Fly ◽  
Maxillary Palps

In the vinegar fly (Drosophila melanogaster), the neuronal pathway that processes olfactory information is organized into multiple layers: a peripheral set of olfactory sensory neurons (OSNs); the primary olfactory center, or antennal lobe (AL); and two second-order neuropils, the mushroom body (MB) and lateral horn (LH). Odorants are detected by the dendrites of OSNs housed in sensilla on the maxillary palps and antennae. The OSN axons converge onto spherical synaptic neuropil within the AL termed glomeruli. OSNs that express the same odorant receptor project to the same glomerulus in a one-to-one fashion, forming discrete olfactory pathways. In the AL, a network of local interneurons (LNs) and projection neurons (PNs) contribute to the first-order processing within the glomeruli. Two types of PNs constitute the principal, parallel output pathways made by PN axons that end in the second-order neuropils of the MB and LH: uniglomerular PNs (uPNs) and multiglomerular PNs (mPNs).

scholarly journals Immature olfactory sensory neurons provide behaviorally useful sensory input to the olfactory bulb

2021 ◽  
Author(s):  
Jane S Huang ◽  
Tenzin Kunkhyen ◽  
Beichen Liu ◽  
Ryan J Muggleton ◽  
Jonathan T Avon ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Sensory Neurons ◽  
Sensory Input ◽  
Odorant Receptors ◽  
Projection Neurons ◽  
Olfactory Sensory Neurons ◽  
Odor Processing ◽  
Newborn Neurons ◽  
Behavioral Assays

Postnatal neurogenesis provides an opportunity to understand how newborn neurons functionally integrate into circuits to restore lost function. Newborn olfactory sensory neurons (OSNs) wire into highly organized olfactory bulb (OB) circuits throughout life, enabling lifelong plasticity and regeneration. Immature OSNs can form functional synapses capable of evoking firing in OB projection neurons. However, what contribution, if any, immature OSNs make to odor processing is unknown. Indeed, because immature OSNs can express multiple odorant receptors, any input that they do provide could degrade the odorant selectivity of input to OB glomeruli. Here, we used a combination of in vivo 2-photon calcium imaging, optogenetics, electrophysiology and behavioral assays to show that immature OSNs provide odor input to the OB, where they form monosynaptic connections with excitatory neurons. Importantly, immature OSNs responded as selectively to odorants as mature OSNs. Furthermore, mice successfully performed odor detection tasks using sensory input from immature OSNs alone. Immature OSNs responded more strongly to low odorant concentrations but their responses were less concentration dependent than those of mature OSNs, suggesting that immature and mature OSNs provide distinct odor input streams to each glomerulus. Together, our findings suggest that sensory input mediated by immature OSNs plays a previously unappreciated role in olfactory-guided behavior.

Olfaction in insects

e-Neuroforum ◽  
2011 ◽  
Vol 17 (3) ◽  
Author(s):  
Silke Sachse ◽  
Jürgen Krieger
Keyword(s):  
Sensory Neurons ◽  
Antennal Lobe ◽  
Projection Neurons ◽  
Cellular Mechanisms ◽  
Dendritic Membrane ◽  
Input Signals ◽  
Crucial Information ◽  
Spontaneous Action ◽  
Specific Receptors ◽  
The Brain

SummaryOdorants provide insects with crucial information about their environment and trigger various insect behaviors. A remarkably sensitive and selective sense of smell allows the animals to detect extremely low amounts of relevant odorants and thereby recognize, e.g., food, conspecifics, and predators. In recent years, significant progress has been made to­wards understanding the molecular elements and cellular mechanisms of odorant detection in the antenna and the principles under­lying the primary processing of olfactory signals in the brain. These findings show that olfactory hairs on the antenna are specifically equipped with chemosensory detector units. They contain several binding proteins, which transfer odorants to specific receptors resid­ing in the dendritic membrane of olfacto­ry sensory neurons (OSN). Binding of odor­ant to the receptor initiates ionotropic and/or metabotropic mechanisms, translating the chemical signal into potential changes, which alter the spontaneous action potential frequency in the axon of the sensory neurons. The odor-dependent action potentials propagate from the antennae along the axon to the brain leading to an input signal with­in the antennal lobe. In the antennal lobe, the first relay station for olfactory information, the input signals are extensively processed by a complex network of local interneurons be­fore being relayed by projection neurons to higher brain centers, where olfactory perception takes place.

scholarly journals Lineage does not regulate the sensory synaptic input of projection neurons in the mouse olfactory bulb

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Luis Sánchez-Guardado ◽  
Carlos Lois
Keyword(s):  
Olfactory Bulb ◽  
Sensory Neurons ◽  
Synaptic Input ◽  
Pyramidal Neurons ◽  
Cell Lineage ◽  
Olfactory Receptors ◽  
Projection Neurons ◽  
Olfactory Sensory Neurons ◽  
Neuronal Progenitors ◽  
Functional Relevance

Lineage regulates the synaptic connections between neurons in some regions of the invertebrate nervous system. In mammals, recent experiments suggest that cell lineage determines the connectivity of pyramidal neurons in the neocortex, but the functional relevance of this phenomenon and whether it occurs in other neuronal types remains controversial. We investigated whether lineage plays a role in the connectivity of mitral and tufted cells, the projection neurons in the mouse olfactory bulb. We used transgenic mice to sparsely label neuronal progenitors and observed that clonally related neurons receive synaptic input from olfactory sensory neurons expressing different olfactory receptors. These results indicate that lineage does not determine the connectivity between olfactory sensory neurons and olfactory bulb projection neurons.

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